Flow restrictor



Aug. 18, 1959 J. o. HRUBY, JR 2,899,978

FLOW RESTRICTOR Filed Jui 9, 1958 I 30 9 I a 31 13. 32

Z'IOHN 0. 'HEUAX-k.

INVENTOR.

United States Patent FLOW RESTRICTQR John 0. Hruby, Jr., Burbank, Califi, assignor to Rain Jet S Corporation, Burbank, Califi, a corporation Application July 9, 1958, Serial vNo. 747,417 3 Claims. c1. 138 -43) 9 This invention relates to restrictors for controlling flow of fluids through tubular conduits, and more particularly to restrictors for use in lawn sprinkler systems.

It is a general object of this invention to provide an improved restrictor which may. be adjusted easily when positioned in a conduit to obtain a desired rate of flow through the conduit. v 1" I I Another object of this invention is to provide a restrictor of the above mentioned character which is simple in construction, easy to install, eflicient in operation, and of relatively low cost.

Further objects and advantages of this invention will appear in the following part of this specification wherein the details of construction and mode of operation of a preferred embodiment are described with reference to the accompanying drawing, in which:

Fig. l is a side elevation, with certain parts being shown in central vertical section, of a portion of a lawn sprinkler system having a restrictor of this invention contained therein;

Fig. 2 is an exploded view of the component parts of the restrictor shown in side elevation; and

Fig. 3 is a cross section through the restrictor taken on line 3-3 of Fig. 1.

Referring to the drawing in greater detail, there is shown a pipe 10 and a pipe-T11 of a lawn sprinkler system. Extending vertically above the pipe T is a riser pipe 12 having a sprinkler head 13 mounted upon the upper end thereof. The sprinkler head is shown for illustration purposes only, and may be of the type illustrated in my Patent No. 2,810,607, issued Ocotber 22, 1957.

A restrictor, embodying this invention and designated generally by reference numeral 16, is positioned between the pipe-T11 and the upstream (lower) end 17 of the riser 12. It comprises a tubular body 18 having a male fitting 19 which is externally screw-threaded for engagement with internal screw threads 20 in the pipe-T11. A downstream (upper) end portion 21 of the body comprises a female fitting which is internally screw-threaded at 22 for receiving the lower end 17 of the riser 12. A bore 24 extends axially through the lower end portion 19 of the body, the rim which defines the downstream (upper) end opening of the bore being designated by numeral 25, and the upstream (lower) end opening of the bore being designated by numeral 26. Inasmuch as the internal diameter of the female portion 21 is greater than that of the bore 24, there is a frusto-conical shoulder 27 between the upper end of the bore and the lower end of inside of the female portion.

The bore 24 receives a plug 29 comprising a head portion 30, a cylindrical stem portion 31, and a coil 32. The coil is substantially cylindrical throughout the greater portion of its length, and its lower end portion 33 is spiralled inwardly to make the lower end opening 34 thereof of a diameter approximating the distance between adjacent turns of the coil. The outside diameter of the cylindrical portion of the coil is slightly less than the "ice,

diameter of the bore 24, and the inside diameter of the coil is about equal to the diameter of the stem portion 31. The upper end portion of the coil fits around the stem portion, there being a recess 35 formed in the side wall of the stem portion adjacent the ,head for receiving end36 of the coil, thus to secure the coil on the stem portion.

There is a projection 38 on the tubular body 18 extending inwardly of the bore 24 adjacent the lower end opening 26. When the coil is inserted into the tubular body and rotated in a clockwise direction, the projection 38 will become engaged between adjacent turns of the coil to serve as a screw thread by which the plug may be advanced downwardly in the bore. The projection is of slightly greater dimension in the thickness thereof (i.e. vertical dimension in the drawing) than the space between adjacent turns of the coil." Thus, the turns of the .coil on respective opposite faces of the projection will be spread apart slightly,;and the tension inthe wire of the coil'will hold the coil secureagainst the projection to prevent inadvertent rotation of the coil in the restrictor.

The head portion of the plug has a slot 49 formed therein for accommodating the tool end of a screwdriver (not shown) for turning the plug in the restrictor body. It will be apparent that as the plug is rotated in a clockwise direction, looking down into the riser, to move the stem portion 31 downwardly into the bore 24, the stem portion will occupy more space within the bore, thereby to confine flow of fluid to between adjacent turns of the coil, and as a result, restrict flow of water to the sprinkler.

In a lawn sprinkler system having a plurality of spaced apart risers and sprinkler heads connected to a common supply pipe 10, a sprinkler located upstream of another in the same horizontal plane will receive water at a higher pressure, and thus will cover a larger area of lawn than will thedownstream sprinkler. two sprinklers are connected to the same supply pipe, but one is positioned at a higher level than the other, the sprinkler at the higher level will ordinarily receive water at a pressure lower than that received by the sprinkler at the lower level.

The restrictor of this invention makes it possible to equalize the flow of water from a plurality of sprinkler heads throughout the sprinkler system. Should it be desired to have one sprinkler cover a larger area than the other, this, too, may be done by employing the restrictor of this invention. As explained in my Patent No. 2,810,607, adjustment of the several restrictors in a lawn sprinkler installation is done before the sprinkler heads are mounted on their risers. Water is then turned on to the supply pipe 10 and the height of the stream of water from each riser is compared with the others. If it is desired that each sprinkler in the system cover a given area of lawn, the several restrictors are adjusted as explained above to produce streams of equal height. After this has been done the sprinkler heads are mounted on the respective risers to complete the installation.

Should there be an accumulation of solid particles by the restrictor coil, the same may be flushed out through the riser pipe by removing the sprinkler head, unscrewing the coil plug from the restrictor body, and then turning the water on for the system to lift the plug out of the riser and to flush out the accumulated solid particles.

While the instant invention has been shown and described herein, in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein, but is to be accorded the full scope of the claims.

What I claim is:

Also, where l. A flow restrictor' for a tubular conduit comprising a' tubular body adapted to be mounted in the conduit for flow through the body, the body having an inside wall defining a bore extending therethrough, a plug member comprising a-stem portion receivablecoaxially in the downstream tend'of the bore, and a cylindricalc'oil -of resilient material having a downstream end portion thereof around the stem portion and secured toi'the plug, the axial length of the coil being substantially greater than that of the stern portion; the outside diameter vof the-stern portion being about equal to 'the inside diameter at the coil, the outside diameter of the coil being about equal t'o'the' diameter of the bore whereby a flow passageway v V 4 ing axially therethrough to define an annular end shoulder at the downstream end of the bore, a plug member com; prising a head, a cylindrical stem and a cylindrical coil, the head being of greater diameter than the bore, the stem being integral with the head and being receivable in the downstream end of the bore, the coil being formed of resilient wire and of an axial length substantially greater than that of the stem,j the space between adjacent turns of the coil being substantially uniform throughout the length of the coil,"the outside diameter of the stern being about equal to the inside diameter of the coil, the outside-diameter of the coil being about equal through the restrictor is provided around the stem portion and between adjacent turns of the coil, and aprojection on'the inside wall of the body extending between apair of adjacent turns in the coil.

2. A flow restrictor according to' claim 1 in which the dimension of saidprojection taken axially of 'the bodyv bore is slightly greater than said space in the coil whereby the coil is flexed axially at the place of engagement thereof with the projection.

3. A flow restrictor for a water pipe system comprising a tubular body adapted to be mounted in' the pipesystem, the body having an inside wall defining a bore extendto the diameter of the bore, a downstream end portion of the 'coil'being secured around the stem, and a 'prm jection on the inside wall of the body extending between a pair of adjacent turns in the coil, the dimension of the projection taken axially of the body bore being slightly greater than said uniform space whereby the coil is flexed axially thereof at the place of engagement of the coil with the projection. p a v r References Cited in the file of this patent UNITED STATES PATENTS 7 1,079,985 Kaminsky Dec.. 2,, 1915 

